Information Schema THREAD_POOL_GROUPS Table

The Information Schema THREAD_POOL_GROUPS table provides details about the thread groups in the thread pool, including active thread counts.

This table is available as of MariaDB 10.5.

The table provides information about thread pool groups, and contains the following columns:

Column	Description
GROUP_ID	the thread group this row is showing data for
CONNECTIONS	the number of clients currently connected to this thread group
THREADS	total number of threads in this group (ACTIVE+STANDBY+LISTENER)
ACTIVE_THREADS	number of threads currently executing a query
STANDBY_THREADS	number of threads in reserve that do not currently execute anything
QUEUE_LENGTH	number of client requests waiting for execution
HAS_LISTENER	whether there is an active listener thread right now, always 1 if thread_pool_dedicated_listener is ON
IS_STALLED	whether there's currently an active worker thread in this group that has exceeded thread_pool_stall_limit time

Setting thread_pool_dedicated_listener will give each group its own dedicated listener, and the listener thread will not pick up work items. As a result, the actual queue size in the table will be more exact, since IO requests are immediately dequeued from poll, without delay.

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